1. Field
Exemplary embodiments of the present invention relate to a head mounted display and a method for displaying contents using the head mounted display. More particularly, the embodiments relate to a head mounted display that is light-weight and supports high resolution and a method for displaying contents using the head mounted display.
2. Discussion of the Background
Recently, the demand for personal display devices increases in accordance with the trend of a decrease in the size of display elements, and display devices are developed which provide the same effect as that of a case where an image is seen with a large screen being disposed at a predetermined distance while an image output from small image display elements is magnified using an optical system, and the eyes are allowed to see a resultant virtual image.
Since most of such devices has a form being worn on the head using a method similar to that of glasses, the devices are called head mounted displays (hereinafter, referred to as HMD). Generally, HMDs are video display systems that form a predetermined image on a single eye or both eyes at a position close to the eyes of a user by using a high-precision optical device included inside thereof.
In order to show such device characteristics, the HMDs are designed such that the focal distance is formed to be very short and have been mainly used for the purpose of implementation of videos of military, medical, and educational video systems, virtual reality systems for entertaining, and the like. However, recently, the HMDs are developed in various forms and are spread in a large quantity in accordance with the trend of an increase in the quality of hardware such as a home or portable audio/video (AV) system (for example, a DVD system, a home theater, or the like) and a wired or wireless computer, and accordingly, the utilization and the use value of the HMDs increase.
A general HMD configures various optical mechanisms using a reflector and a high magnification lens for providing a wide field of view. An HMD that provides a wide field of view and high resolution has a large size and a heavy weight. In addition, since the constituent devices are complicated, and a high-level optical technology is necessary, the price of such an HMD is very high.
A general HMD includes a lens that is used for shortening the focal distance on the inside thereof. As illustrated in FIG. 1, in an optical system that uses a single lens 2, a distance (focal distance a) from a display unit 1 to the lens 2 and a distance b between the lens and an eyeball 10 need to be secured to some degree. The reason for this is that a lens having a short focal distance forms an image with a high magnification ratio, whereby the aberration is very high. In order to reduce the aberration, although a lens such as an LEEP has been devised, a distance of about ten and several cm from the display unit 1 needs to be secured due to the limitation of the magnification ratio. Accordingly, the volume of the HMD is very large, and it is inconvenient to wear the HMD. In order to wear such an HMD, a holding unit of a large volume is necessary for holding the HMD device on the head. Therefore, a user may wear the HMD only in a particular situation, and accordingly, it is inappropriate for a general user to use the HMD in everyday life.
In addition, generally, the price of a lens that is used in the HMD is high. In order to realize a short focal point and a wide field of view, a high-level technology is required, and accordingly, the price of the HMD is very high. In addition, in a wide-angle short-focal point lens used in the HMD, there is a difference between the magnification ratios of a center portion and an edge portion, whereby the distortion of a video occurs. Due to such distortion, a user experiences a sense of difference and dizziness. Accordingly, it is difficult to implement an HMD that supports a wide field of view. In other words, a general HMD has a problem in that a wide field of view may not be secured with a minimal volume and a minimal weight.